He served as High Sheriff of Kerry in 1759, and in 1760 was made a member of the Privy Council of Ireland. In 1790 he built a new stately home for his family overlooking Dingle harbour, called Burnham Manor. On 18 June 1793, over 4,000 people marched in Dingle to protest against high rents and the establishment of a local militia. Mullins, who assumed responsibility for the town on behalf of the Crown, brought in 70 soldiers from Limerick to break up the demonstration. The riot was quelled when soldiers were ordered to shoot at the crowd, and 14 farmers were killed with many others being injured.[3]